Re: NAT64 in RA, draft-ietf-6man-ra-pref64

Hi Dusan,

On Fri, Jul 5, 2019 at 6:19 AM Mudric, Dusan (Dusan) <dmudric@avaya.com> wrote:
> What is the best reference document for a Translator that facilitates:
>
> - IPv4only - to - IPv6only, and

https://tools.ietf.org/html/rfc7755

> - IPv6only - to - IPv4Only

https://tools.ietf.org/html/rfc6146

> clients message exchanges?
>
> Is this communication bidirectional or works only from IPv6only-to-IPv4only client (meaning IPv6only client has to initiate the communication)?
>
> How can Translator or DNS64 tell IPv6 only client the IP of IPv4 only client, and vice versa?

In a nutshell:

IPv6-only client asks DNS64 server for AAAA for, let's say, ipv4only.example.net
As that server is IPv4-onl, does not have AAAA RR, the DNS64 server
synthesise a new AAAA using an IPv6 prefix (usually /96 - the
Well-Known Prefix is 64:ff9b::/96) and IPv4 address from the A
RR. The algorithm described in rfc6147

So if ipv4only.example.net has an IPv4 address 192.0.2.2, then DNS64
will return 64:ff9b::192.0.2.2 as AAAA RR.
The ipv6-only client would initiate a connection to that address . As
NAT64 prefix is supposed to be routed to the NAT64 device, that device
would translate IPv6 packet to IPv4 packet using the algorithm
described in https://tools.ietf.org/html/rfc6052.

> > -----Original Message-----
> > From: Fred Baker <fredbaker.ietf@gmail.com>
> > Sent: Wednesday, July 3, 2019 3:32 PM
> > To: Mudric, Dusan (Dusan) <dmudric@avaya.com>
> > Cc: 6man <6man@ietf.org>; IPv6 Operations <v6ops@ietf.org>
> > Subject: Re: NAT64 in RA, draft-ietf-6man-ra-pref64
> >
> >
> >
> > > On Jul 3, 2019, at 12:01 PM, Mudric, Dusan (Dusan) <dmudric@avaya.com>
> > wrote:
> > >
> > > [Dusan] Please clarify how IPv4-only host can reach IPv6 only host, and vice
> > versa. Also, how IPv6 only host can know IPv4 address of IPv4 only host,
> > assuming IPv4 only host is in a public domain?
> >
> > Simple. Using a Translator, either at layer 3 or above it. Any other way
> > doesn't work.
> > --------------------------------------------------------------------------------
> > The fact that there is a highway to hell and a stairway to heaven is an
> > interesting comment on projected traffic volume...
>
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-- 
SY, Jen Linkova aka Furry